Re: [Intel-wired-lan] [PATCH v6 7/7] ixgbevf: eliminate duplicate barriers on weakly-ordered archs

On Fri, Mar 23, 2018 at 11:27 AM, Sinan Kaya [off-list ref] wrote:

On 3/23/2018 2:25 PM, Alexander Duyck wrote:

quoted

quoted

+               /* We need this if more than one processor can write to our tail
+                * at a time, it synchronizes IO on IA64/Altix systems
+                */
+               mmiowb();
        }

The mmiowb shouldn't be needed for Rx. Only one CPU will be running
NAPI for the queue and we will synchronize this with a full writel
anyway when we re-enable the interrupts.

OK. I can fix this on the next version. I did a blanket search and replace for
my writel_relaxed() changes as I don't know the code well enough.

Please point me to the redundant ones.

So from what I can tell only this file and i40e needed any additional
mmiowb calls added. The rest are not needed.

- Alex